1. Field of the Invention
The invention relates to the technical field of image processing and, more particularly, to a method and system for correcting defective pixels of a color image.
2. Description of Related Art
A color image processing system essentially includes an image capture unit, an image reconstructing and processing unit, an image display and an image compression unit. The image capture unit includes an image sensor, which is a sensitive device consisting of multiple photodiodes in a 2D array. The sensitive device converts an intensity of a sensed light into an electronic signal for the image reconstructing and processing unit in order to further perform the corresponding image processing. However, due to the unavoidable errors in process, the photodiodes causes faults in the image sensor. Namely, the image sensor has one or more defective pixels to cause inaccurate photosensitive conversion, so as to form dark dots or bright dots on an captured image.
To overcome this problem, the U.S. Pat. No. 6,741,754 granted to Hamilton, Jr. for a “Correcting for defects in a digital image taken by an image sensor caused by pre-existing defects in two pixels in adjacent columns of an image sensor” has taught that an electrical detection is performed directly on an image sensor to thus obtain the positions of the defective pixels and record the positions in a defect map. Accordingly, a defective pixel is corrected by the neighboring pixel values in accordance with the position of the defective pixel recorded in the defect map during the image processing. However, if the defect map is not updated immediately after the detection and recording, the defective pixels caused by the decaying photodiodes are not corrected.
To overcome this problem, US published application No. 2004/0119856 entitled “circuit and method for correction of defect pixel” has taught that a defective detection is performed real-time on a Bayer image to accordingly improve the disadvantage of using the defect map to record defective pixels. However, such a defective detection cannot find defective pixels on a Bayer image effectively because the inherent pixel crosstalk effect caused on an illuminated pixel.
Therefore, it is desirable to provide an improved method and system for correcting defective pixels of a color image to mitigate and/or obviate the aforementioned problems.